If I own rank 3 of Breath

[Caelin-boulderfist (Caelin)]

Why can my alts buy the SAME essences but bc my main is a dps only my healer/tank alts are screwed?

You can, what you actually want is a different essence than the one your main bought.

[Vhx-black-dragonflight]

@Retallìca-illidan

I want a blizzard answer to this.

They gave an answer to this on the original post. See below:

@Kaivax

While ordinarily each specific Essence must be learned in order to unlock it for other characters via MOTHER, all Essences associated with Nazjatar and Mechagon reputations will be available if any other different character has earned any of the Essences available from that reputation.

“While ordinarily each specific Essence must be learned in order to unlock it for other characters” means everything that isn’t the Nazj/Mech rep-based essences must specifically be learned to be unlocked for alts.